This invention relates to power transmitting clutches and more particularly to such clutches having spring dampers with excursion limiting devices.
Prior art damper mechanisms for power transmitting clutches generally provide for limiting angular excursion by utilizing the solid height of the spring. While this approach is effective, it quite often results in inordinate stresses being induced within the springs. To counter this condition, it has been suggested that a positive stop member be placed on either the input member or output member of the clutch in a position to abut the other member thus limiting the angular excursion of the input member relative to the output member. The stop member is usually a pin or other axially extending member secured to either the input or output member and extending into the path of travel of the other member.
While this scheme is effective with single phase dampers, it loses some of its effectiveness with serially arranged spring dampers. In serially arranged dampers, at least one set of the damper springs must reach solid height to take full advantage of the spring rates unless centrally disposed pins or extended spring seats are employed. These members must be installed at assembly therefore require additional processing.
The use of rivets secured to one member, i.e., the input, and a surface on the other member, i.e., output can operate as the stop devices. These devices require additional installation operations during the manufacture of the clutch assembly. Each rivet must be installed or positioned during manufacture. The insertion of one or more rivets can be overlooked resulting in the damper reverting to solid spring height as the stop structure.